Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment. Some semiconductor devices comprise integrated circuit dies, for example. Dozens or hundreds of integrated circuit dies are typically manufactured on a single semiconductor wafer and are later singulated by sawing the integrated circuits along scribe lines. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon.
Chemical-mechanical polishing (CMP) is one type of process used in the manufacture of semiconductor devices. CMP is a process used to smooth and planarize surfaces of wafers using a combination of chemical and mechanical forces. Integrated circuit dies in wafer form are placed into a chamber of a CMP tool and are planarized or polished at various stages of a manufacturing process. CMP processes may be used to form planar surfaces on dielectric layers, semiconductive layers, and conductive material layers of a wafer, as examples.
CMP tools typically have a rotatable platen with a polishing pad attached to the platen. In some CMP processes, a semiconductor wafer is placed upside down against the polishing pad using a predetermined amount of pressure. A liquid dispersion referred to as a slurry that contains chemicals and microabrasive grains is applied to the polishing pad during the CMP process while the wafer is held against the rotating polishing pad. The wafer is also rotated in some applications.